Soil and it’s characteristics
Moroccan common core english option
Horizons:
vertical
columns
of
soil
exposure
Color of soil depends
on how the soil is
formed and what it
contains
O. (Organic) Most living
organisms carrie on their main
activities remains of dead plants
are
found
and
slowly
decomposing
A. (Surface or topsoil) Most
productive horizon, where most
organisms and organic matter is
found humus forms
B. (Subsoil) Soil hasn’t quite
formed yet, not enough organic
matter to be productive, where
root systems are penetrated
C.
(Substratum)
Transition
between bedrock and productive
soils
R. (bedrock) unweathered parent
rock
Soil’s roles
growth
releasing , absorbing gases.
habitat,
absorb
animals
hold
release
nutrients
alter,
Carbon,
engineering media
aquifer
Living filter
dynamic
The same
The same
Soil’s physical characteristics : grain size
• Soil's physical characteristics include grain size, which refers to the
size of the mineral components within the soil. These mineral
components are classified into three main types of grains based on
their size."
Clay
Silt
Sand
granulometric analysis
• The basic concept to get soil’s
texture in a granulometric analysis
of soil
• Granulometric analysis refers to
the process of determining the
particle size distribution of a
granular material, such as soil,
sediment, or aggregate. It involves
separating and measuring particles
of different sizes within the
material
to
understand
its
composition and characteristics
• The analysis is typically performed
through methods like sieving or
sedimentation, where the sample
is divided into fractions based on
particle size. The weight or volume
of each fraction is then measured,
and the data is used to calculate
the percentage or cumulative
percentage of particles within
specific size ranges.
Soil’s physical characteristics : soil’s texture
• Soil texture refers to the relative
proportion of sand, silt, and clay particles
in a given soil. It describes the physical
composition of soil and is determined by
the size of the mineral particles it
contains
• Given that we determine soil texture by
calculating the percentages of clay, silt,
and sand in a soil sample, we rely on a
graphical approach in the form of a soil
texture triangle.
% Clay
soil texture triangle
• The soil texture triangle is a graphical
representation that helps determine
the texture of a soil sample by
plotting the percentages of sand, silt,
and clay in it. It consists of a
triangular diagram divided into
sections, with each section
representing a different soil texture.
By locating the point where the three
percentages intersect on the triangle,
one can determine the soil texture
classification.
% Clay
How to use
the
triangle ?
• Let’s suppose you have the
following percentages.
• Clay 30%
• Silt 40%
• Sand 30%
• you project the percentage of each axis
towards the complementary percentage
of the contiguous axis and parallel to the
third axis.
• The meeting point of each projected line
• Gives the soil texture
Worked
example
• Let’s suppose you have the
following percentages.
• Clay 10%
• Silt 40%
• Sand 50%
Worked
example
• Let’s suppose you have the
following percentages.
• Clay 30%
• Silt 20%
• Sand 50%